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Vucinic L, O’Connell D, Teixeira R, Coxon C, Gill L. Flow Cytometry and Fecal Indicator Bacteria Analyses for Fingerprinting Microbial Pollution in Karst Aquifer Systems. WATER RESOURCES RESEARCH 2022; 58:e2021WR029840. [PMID: 35859924 PMCID: PMC9285701 DOI: 10.1029/2021wr029840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/23/2022] [Accepted: 04/01/2022] [Indexed: 06/15/2023]
Abstract
Microbial pollution of aquifers is a persistent water quality problem globally which poses significant risks to public health. Karst aquifer systems are exceptionally vulnerable to pollution from fecal contamination sources as a result of rapid recharge of water from the surface via discrete pathways linked to highly conductive, solutionally enlarged conduits alongside strong aquifer heterogeneity. Consequently, rapid changes in microbial water quality, which are difficult to monitor with expensive and time-consuming conventional microbiological methods, are a major concern in karst environments. This study examined flow cytometric (FCM) fingerprinting of bacterial cells in groundwater together with fecal indicator bacteria (FIB) at nine separate karst springs of varying catchment size over a 14 month period in order to assess whether such a technique can provide faster and more descriptive information about microbial pollution through such karst aquifer systems. Moreover, the data have also been evaluated with respect to the potential of using turbidity as an easy-to-measure proxy indicator of microbial pollution in a novel way. We argue that FCM provides additional data from which enhanced insights into fecal pollution sources and its fate and transport in such karst catchments can be gained. We also present valuable new information on the potential and limitations of turbidity as an indicator of fecal groundwater contamination in karst. FCM has the potential to become a more widely used tool in the field of contaminant hydrogeology.
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Affiliation(s)
- Luka Vucinic
- Department of Civil, Structural and Environmental EngineeringUniversity of DublinTrinity CollegeDublinIreland
| | - David O’Connell
- Department of Civil, Structural and Environmental EngineeringUniversity of DublinTrinity CollegeDublinIreland
| | - Rui Teixeira
- Department of Civil, Structural and Environmental EngineeringUniversity of DublinTrinity CollegeDublinIreland
| | - Catherine Coxon
- Department of Geology and Trinity Centre for the EnvironmentUniversity of DublinTrinity CollegeDublinIreland
| | - Laurence Gill
- Department of Civil, Structural and Environmental EngineeringUniversity of DublinTrinity CollegeDublinIreland
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Assessing the Karst Groundwater Quality and Hydrogeochemical Characteristics of a Prominent Dolomite Aquifer in Guizhou, China. WATER 2020. [DOI: 10.3390/w12092584] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Karst groundwater is one of the primary water resources in most provinces of Southwestern China where karst topography is strongly featured. In Guizhou Province, a prominent geologic sedimentary formation is the dolomite stratum which exists as the restricted platform facies and potentially provides a large reservoir for drinking water. A proper understanding and evaluation of its hydrogeochemical characteristics and water quality is the key to ensuring the drinking water safety. In the present study, groundwater samples were collected from 25 locations of the dolomite aquifer across Guizhou to determine their major chemical compounds, including the cations (K+, Na+, Ca2+, Mg2+) and the anions (HCO3−, F−, Cl−, NO3−, SO42−), as well as the pH, total hardness, and total dissolved solids. HCO3− and Ca2+ were found to be the dominant anion and cation, respectively, which is characteristic of typical karst groundwater and supports the overall observation of a slightly weak acid to weak alkaline environment in the studied groundwater, as the pH measurements ranged from 6.80 to 8.37. Fuzzy comprehensive evaluation method is used to evaluate the groundwater quality based on typical drinking water safety standard. The results show that the groundwater in most of the studied aquifers is of reasonably good quality. However, in some aquifers, concentrations of NO3− and/or SO42− were found to be excessively high. Overall, the studied dolomite aquifer in its natural environment as investigated in the present study can be considered as a potential geological stratum for water resources exploitation in Guizhou.
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Epting J, Page RM, Auckenthaler A, Huggenberger P. Process-based monitoring and modeling of Karst springs - Linking intrinsic to specific vulnerability. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:403-415. [PMID: 29289788 DOI: 10.1016/j.scitotenv.2017.12.272] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/22/2017] [Accepted: 12/22/2017] [Indexed: 06/07/2023]
Abstract
The presented work illustrates to what extent field investigations as well as monitoring and modeling approaches are necessary to understand the high discharge dynamics and vulnerability of Karst springs. In complex settings the application of 3D geological models is essential for evaluating the vulnerability of Karst systems. They allow deriving information on catchment characteristics, as the geometry of aquifers and aquitards as well as their displacements along faults. A series of Karst springs in northwestern Switzerland were compared and Karst system dynamics with respect to qualitative and quantitative issues were evaluated. The main objective of the studies was to combine information of catchment characteristics and data from novel monitoring systems (physicochemical and microbiological parameters) to assess the intrinsic vulnerability of Karst springs to microbiological contamination with simulated spring discharges derived from numerical modeling (linear storage models). The numerically derived relation of fast and slow groundwater flow components enabled us to relate different sources of groundwater recharge and to characterize the dynamics of the Karst springs. Our study illustrates that comparably simple model-setups were able to reproduce the overall dynamic intrinsic vulnerability of several Karst systems and that one of the most important processes involved was the temporal variation of groundwater recharge (precipitation, evapotranspiration and snow melt). Furthermore, we make a first attempt on how to link intrinsic to specific vulnerability of Karst springs, which involves activities within the catchment area as human impacts from agriculture and settlements. Likewise, by a more detailed representation of system dynamics the influence of surface water, which is impacted by release events from storm sewers, infiltrating into the Karst system, could be considered. Overall, we demonstrate that our approach can be the basis for a more flexible and differentiated management and monitoring of raw-water quality of Karst springs.
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Affiliation(s)
- Jannis Epting
- Department of Environmental Sciences, Applied and Environmental Geology, University of Basel, Switzerland.
| | | | - Adrian Auckenthaler
- Department of Environmental Protection and Energy, Canton Basel-Landschaft, Liestal, Switzerland.
| | - Peter Huggenberger
- Department of Environmental Sciences, Applied and Environmental Geology, University of Basel, Switzerland.
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Page RM, Besmer MD, Epting J, Sigrist JA, Hammes F, Huggenberger P. Online analysis: Deeper insights into water quality dynamics in spring water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 599-600:227-236. [PMID: 28477479 DOI: 10.1016/j.scitotenv.2017.04.204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/26/2017] [Accepted: 04/27/2017] [Indexed: 06/07/2023]
Abstract
We have studied the dynamics of water quality in three karst springs taking advantage of new technological developments that enable high-resolution measurements of bacterial load (total cell concentration: TCC) as well as online measurements of abiotic parameters. We developed a novel data analysis approach, using self-organizing maps and non-linear projection methods, to approximate the TCC dynamics using the multivariate data sets of abiotic parameter time-series, thus providing a method that could be implemented in an online water quality management system for water suppliers. The (TCC) data, obtained over several months, provided a good basis to study the microbiological dynamics in detail. Alongside the TCC measurements, online abiotic parameter time-series, including spring discharge, turbidity, spectral absorption coefficient at 254nm (SAC254) and electrical conductivity, were obtained. High-density sampling over an extended period of time, i.e. every 45min for 3months, allowed a detailed analysis of the dynamics in karst spring water quality. Substantial increases in both the TCC and the abiotic parameters followed precipitation events in the catchment area. Differences between the parameter fluctuations were only apparent when analyzed at a high temporal scale. Spring discharge was always the first to react to precipitation events in the catchment area. Lag times between the onset of precipitation and a change in discharge varied between 0.2 and 6.7h, depending on the spring and event. TCC mostly reacted second or approximately concurrent with turbidity and SAC254, whereby the fastest observed reaction in the TCC time series occurred after 2.3h. The methodological approach described here enables a better understanding of bacterial dynamics in karst springs, which can be used to estimate risks and management options to avoid contamination of the drinking water.
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Affiliation(s)
- Rebecca M Page
- Endress+Hauser (Schweiz) AG, Kägenstrasse 2, 4153 Reinach, Switzerland.
| | - Michael D Besmer
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology, Dübendorf, Switzerland; Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland
| | - Jannis Epting
- Applied and Environmental Geology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Jürg A Sigrist
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology, Dübendorf, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology, Dübendorf, Switzerland
| | - Peter Huggenberger
- Applied and Environmental Geology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
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Besmer MD, Hammes F, Sigrist JA, Ort C. Evaluating Monitoring Strategies to Detect Precipitation-Induced Microbial Contamination Events in Karstic Springs Used for Drinking Water. Front Microbiol 2017; 8:2229. [PMID: 29213255 PMCID: PMC5703154 DOI: 10.3389/fmicb.2017.02229] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/30/2017] [Indexed: 01/15/2023] Open
Abstract
Monitoring of microbial drinking water quality is a key component for ensuring safety and understanding risk, but conventional monitoring strategies are typically based on low sampling frequencies (e.g., quarterly or monthly). This is of concern because many drinking water sources, such as karstic springs are often subject to changes in bacterial concentrations on much shorter time scales (e.g., hours to days), for example after precipitation events. Microbial contamination events are crucial from a risk assessment perspective and should therefore be targeted by monitoring strategies to establish both the frequency of their occurrence and the magnitude of bacterial peak concentrations. In this study we used monitoring data from two specific karstic springs. We assessed the performance of conventional monitoring based on historical records and tested a number of alternative strategies based on a high-resolution data set of bacterial concentrations in spring water collected with online flow cytometry (FCM). We quantified the effect of increasing sampling frequency and found that for the specific case studied, at least bi-weekly sampling would be needed to detect precipitation events with a probability of >90%. We then proposed an optimized monitoring strategy with three targeted samples per event, triggered by precipitation measurements. This approach is more effective and efficient than simply increasing overall sampling frequency. It would enable the water utility to (1) analyze any relevant event and (2) limit median underestimation of peak concentrations to approximately 10%. We conclude with a generalized perspective on sampling optimization and argue that the assessment of short-term dynamics causing microbial peak loads initially requires increased sampling/analysis efforts, but can be optimized subsequently to account for limited resources. This offers water utilities and public health authorities systematic ways to evaluate and optimize their current monitoring strategies.
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Affiliation(s)
- Michael D Besmer
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.,Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Jürg A Sigrist
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Christoph Ort
- Department of Urban Water Management, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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Besmer MD, Hammes F. Short-term microbial dynamics in a drinking water plant treating groundwater with occasional high microbial loads. WATER RESEARCH 2016; 107:11-18. [PMID: 27783929 DOI: 10.1016/j.watres.2016.10.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 09/29/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
Short-term fluctuations in bacterial concentrations in drinking water systems, occurring on time scales of hours-to-weeks, are essentially unexplored due to a lack of microbial monitoring tools that allow high frequency measurements. Here, we applied fully automated online flow cytometry to measure the total cell concentrations (TCC) in both raw water (karstic groundwater) and treated water (flocculation - ultrafiltration (UF) - ozonation - granular active carbon (GAC) filtration) during a period of 70 days at high temporal resolution (n > 4000 for both water types). We detected and characterized in considerable detail aperiodic fluctuations in the raw water following regional precipitation, with TCC increasing up to 50-fold from a dry weather baseline of approximately 120 cells μl-1 to an event peak of > 5000 cells μl-1. Moreover, we observed the buffering of the treatment plant against these fluctuations, but in addition we recorded a completely unexpected periodic fluctuation of TCC in the treated water after GAC filtration. We concluded that the latter was the result of fluctuating water abstraction from the treatment plant reservoir by two connected water utilities, which resulted in variations in water throughput in the plant. This in turn influenced bacterial detachment and dilution in the GAC filter. This study provides strong evidence of multiple different microbial dynamics occurring in a drinking water treatment system. Given numerous possible sources of natural and operational fluctuations in raw water and drinking water treatment plants, such microbial fluctuations should be expected in many systems. The high-frequency monitoring approach presented herein can improve the understanding and eventual mitigation of such fluctuations.
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Affiliation(s)
- Michael D Besmer
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland; Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zürich, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
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Ghasemizadeh R, Yu X, Butscher C, Padilla IY, Alshawabkeh A. Improved regional groundwater flow modeling using drainage features: a case study of the central northern karst aquifer system of Puerto Rico (USA). HYDROGEOLOGY JOURNAL 2016; 24:1463-1478. [PMID: 30416370 PMCID: PMC6224168 DOI: 10.1007/s10040-016-1419-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/14/2016] [Indexed: 05/19/2023]
Abstract
In northern Puerto Rico (USA), subsurface conduit networks with unknown characteristics, and surface features such as springs, rivers, lagoons and wetlands, drain the coastal karst aquifers. In this study, drain lines connecting sinkholes and springs are used to improve the developed regional model by simulating the drainage effects of conduit networks. Implemented in an equivalent porous media (EPM) approach, the model with drains is able to roughly reproduce the spring discharge hydrographs in response to rainfall. Hydraulic conductivities are found to be scale dependent and significantly increase with higher test radius, indicating scale dependency of the EPM approach. Similar to other karst regions in the world, hydraulic gradients are steeper where the transmissivity is lower approaching the coastline. This study enhances current understanding of the complex flow patterns in karst aquifers and suggests that using a drainage feature improves modeling results where available data on conduit characteristics are minimal.
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Affiliation(s)
- Reza Ghasemizadeh
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Xue Yu
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
| | - Christoph Butscher
- Department of Engineering Geology, Institute of Applied Geosciences, Karlsruhe Institute of Technology, 76131, Karlsruhe, Germany
| | - Ingrid Y. Padilla
- Department of Civil Engineering and Surveying, University of Puerto Rico, Mayaguez, PR 00682, USA
| | - Akram Alshawabkeh
- Department of Civil and Environmental Engineering, Northeastern University, Boston, MA 02115, USA
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8
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Equivalent Porous Media (EPM) Simulation of Groundwater Hydraulics and Contaminant Transport in Karst Aquifers. PLoS One 2015; 10:e0138954. [PMID: 26422202 PMCID: PMC4589392 DOI: 10.1371/journal.pone.0138954] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/05/2015] [Indexed: 11/19/2022] Open
Abstract
Karst aquifers have a high degree of heterogeneity and anisotropy in their geologic and hydrogeologic properties which makes predicting their behavior difficult. This paper evaluates the application of the Equivalent Porous Media (EPM) approach to simulate groundwater hydraulics and contaminant transport in karst aquifers using an example from the North Coast limestone aquifer system in Puerto Rico. The goal is to evaluate if the EPM approach, which approximates the karst features with a conceptualized, equivalent continuous medium, is feasible for an actual project, based on available data and the study scale and purpose. Existing National Oceanic Atmospheric Administration (NOAA) data and previous hydrogeological U. S. Geological Survey (USGS) studies were used to define the model input parameters. Hydraulic conductivity and specific yield were estimated using measured groundwater heads over the study area and further calibrated against continuous water level data of three USGS observation wells. The water-table fluctuation results indicate that the model can practically reflect the steady-state groundwater hydraulics (normalized RMSE of 12.4%) and long-term variability (normalized RMSE of 3.0%) at regional and intermediate scales and can be applied to predict future water table behavior under different hydrogeological conditions. The application of the EPM approach to simulate transport is limited because it does not directly consider possible irregular conduit flow pathways. However, the results from the present study suggest that the EPM approach is capable to reproduce the spreading of a TCE plume at intermediate scales with sufficient accuracy (normalized RMSE of 8.45%) for groundwater resources management and the planning of contamination mitigation strategies.
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9
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Murphy S, Jordan P, Mellander PE, O' Flaherty V. Quantifying faecal indicator organism hydrological transfer pathways and phases in agricultural catchments. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 520:286-299. [PMID: 25840482 DOI: 10.1016/j.scitotenv.2015.02.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/19/2015] [Accepted: 02/05/2015] [Indexed: 06/04/2023]
Abstract
Faecal indicator organisms (FIOs) can impact on water quality and pose a health and environmental risk. The transfer of FIOs, such as Escherichia coli (E. coli), from land to water is driven by hydrological connectivity and may follow the same flowpaths as nutrients, from agricultural and human sources. This study investigated E. coli transfer in two catchment areas with high source and transport pressures. These pressures were: organic phosphorus (P) loading; human settlement; conduits and fissures in a grassland karst area; and clay rich and impermeable soils in a mixed arable area. The occurrence of E. coli and its transport pathways, along with the pathways of nutrients, were studied using a combination of targeted FIO sampling, during different hydrological phases and events, and high resolution nutrient analysis. The quick flow component in both catchments was found to be a more potent vector for E. coli, and was coincident with the total P flowpaths using a P Loadograph Recession Analysis (LRA). The karst grassland catchment was found to be a transport limited system and the mixed arable catchment a source limited system. Hence, despite the grassland catchment being a potentially higher FIO source, the E. coli loads leaving the catchment were low compared to the mixed arable catchment. E. coli load whole-event comparisons also indicated that the grassland karst transfers tended to be much lower on falling phases of runoff, while the arable catchment, over greywacke and mudstone geology, showed little change between the phases. Furthermore, the arable catchment showed asymptotic decline of sustained E. coli loads towards low flows, which may be indicative of chronic point sources. These results indicate the dominance of transport mechanisms over source mechanisms for mass E. coli loads and also chronic loads during low flow. These will be important considerations for risk assessment and mitigation.
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Affiliation(s)
- S Murphy
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Ireland; Environmental Change Institute, National University of Ireland, Galway, Ireland.
| | - P Jordan
- School of Environmental Sciences, Ulster University, Coleraine, N. Ireland, UK.
| | - P-E Mellander
- Agricultural Catchments Programme, Teagasc, Johnstown Castle, Wexford, Ireland
| | - V O' Flaherty
- Environmental Change Institute, National University of Ireland, Galway, Ireland
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Besmer MD, Weissbrodt DG, Kratochvil BE, Sigrist JA, Weyland MS, Hammes F. The feasibility of automated online flow cytometry for in-situ monitoring of microbial dynamics in aquatic ecosystems. Front Microbiol 2014; 5:265. [PMID: 24917858 PMCID: PMC4040452 DOI: 10.3389/fmicb.2014.00265] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 05/15/2014] [Indexed: 01/22/2023] Open
Abstract
Fluorescent staining coupled with flow cytometry (FCM) is often used for the monitoring, quantification and characterization of bacteria in engineered and environmental aquatic ecosystems including seawater, freshwater, drinking water, wastewater, and industrial bioreactors. However, infrequent grab sampling hampers accurate characterization and subsequent understanding of microbial dynamics in all of these ecosystems. A logic technological progression is high throughput and full automation of the sampling, staining, measurement, and data analysis steps. Here we assess the feasibility and applicability of automated FCM by means of actual data sets produced with prototype instrumentation. As proof-of-concept we demonstrate examples of microbial dynamics in (i) flowing tap water from a municipal drinking water supply network and (ii) river water from a small creek subject to two rainfall events. In both cases, automated measurements were done at 15-min intervals during 12-14 consecutive days, yielding more than 1000 individual data points for each ecosystem. The extensive data sets derived from the automated measurements allowed for the establishment of baseline data for each ecosystem, as well as for the recognition of daily variations and specific events that would most likely be missed (or miss-characterized) by infrequent sampling. In addition, the online FCM data from the river water was combined and correlated with online measurements of abiotic parameters, showing considerable potential for a better understanding of cause-and-effect relationships in aquatic ecosystems. Although several challenges remain, the successful operation of an automated online FCM system and the basic interpretation of the resulting data sets represent a breakthrough toward the eventual establishment of fully automated online microbiological monitoring technologies.
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Affiliation(s)
- Michael D Besmer
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland ; Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich Zürich, Switzerland
| | - David G Weissbrodt
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland ; Institute of Environmental Engineering, Chair of Process Engineering in Urban Water Management, ETH Zürich Zürich, Switzerland
| | - Bradley E Kratochvil
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland
| | - Jürg A Sigrist
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland
| | - Mathias S Weyland
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag - Swiss Federal Institute for Aquatic Science and Technology Dübendorf, Switzerland
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11
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Shabarova T, Widmer F, Pernthaler J. Mass effects meet species sorting: transformations of microbial assemblages in epiphreatic subsurface karst water pools. Environ Microbiol 2013; 15:2476-88. [PMID: 23614967 DOI: 10.1111/1462-2920.12124] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 02/21/2013] [Accepted: 02/25/2013] [Indexed: 11/29/2022]
Abstract
We investigated the transformations of the microbial communities in epiphreatic karst cave pools with different flooding frequencies. Fingerprinting of 16S rRNA genes was combined with microscopic and sequence analysis to examine if source water would transport comparable microbial inocula into the pools at consecutive flood events, and to assess possible effects of residence time on the microbial assemblages during stagnant periods. Variability in the concentrations of dissolved organic carbon and conductivity indicated differences between floods and changes of pool water over time. High numbers of Betaproteobacteria affiliated with Methylophilaceae and Comamonadaceae were introduced into the pools during floodings. While the former persisted in the pools, the latter exhibited considerable microdiversification. These Betaproteobacteria might thus represent core microbial groups in karst water. A decrease in the estimated total diversity of the remaining bacterial taxa was apparent after a few weeks of residence: Some were favoured by stagnant conditions, whereas the majority was rapidly outcompeted. Thus, the microbial communities consisted of different components governed by complementary assembly mechanisms (dispersal versus environmental filtering) upon introduction into the pools. High overlap of temporary and persistent community members between samplings from two winters, moreover, reflected the seasonal recurrence of the studied microbial assemblages.
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Affiliation(s)
- Tanja Shabarova
- Limnological Station, Institute of Plant Biology, University of Zurich, Seestr. 187, CH-8802, Kilchberg, Switzerland
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12
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Morasch B. Occurrence and dynamics of micropollutants in a karst aquifer. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 173:133-137. [PMID: 23202643 DOI: 10.1016/j.envpol.2012.10.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 10/04/2012] [Accepted: 10/10/2012] [Indexed: 05/19/2023]
Abstract
Karst systems represent important yet vulnerable drinking water resources. A wide spectrum of pollutants may be released into karst groundwater from agriculture, livestock farming, private households, and industry. This work provides an overview on the occurrence and dynamics of micropollutants in a karst system of the Swiss Jura. Ten months of intensive monitoring for micropollutants confirmed that the swallow hole draining an agricultural plain was the main entry path for pesticides into the karst system and the two connected springs. Elevated fungicide concentrations in winter and occasional quantification of pharmaceuticals suggested wood- or façade treatment and domestic sewer as additional sources of contamination. A continuous atrazine signal in the low ng/L range might affect the autochthonous endokarst microbial community and represents a potential risk for the human population through karst groundwater.
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Affiliation(s)
- Barbara Morasch
- Laboratoire de Chimie Environnementale, EPFL - ENAC - LCE, Bâtiment GR, Station 2, CH-1015 Lausanne, Switzerland.
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